Understanding reward and withdrawal mechanisms underlying habitual caffeine use

Caffeine is the most widely consumed psychoactive drug and is also a food additive found in many foods and beverages. To date, research (some completed by Yeomans/Stafford) has demonstrated the characteristics of caffeine in terms of its withdrawal effects on mood, cognition and preference, but the more fundamental questions on the neural mechanisms underlying habitual caffeine use and deprivation state remain unknown. This is important to understand as it will reveal how acquiring a liking for caffeine is linked to particular brain pathways (involving adenosine) and thereby contribute to questions of plasticity and addiction. This project will firstly use a combination of behavioural and neural (fMRI) measures to characterise the long-term effects of habitual caffeine consumption and acute withdrawal. This will be followed by studies testing how acute caffeine withdrawal increases wanting and liking for caffeine-related stimuli, and then how these are expressed through learned associations between cues predicting caffeine use and the pharmacological consequences of caffeine consumption. The student will receive state-of-the-art training in human learning and psychopharmacology, in fMRI testing (at Sussex) and behavioural analyses (at Portsmouth). The outcomes of this research aim to further our understanding of the basic mechanisms that underlie our affinity to consume caffeinated products, with potential impact on policy and product formulation.